Optimization of start-up power mode of rotation mechanism of manipulator crane with a cylindrical articulated load suspension

The problem of increasing the efficiency of the crane-manipulator by choosing the modes of movement of the swing mechanism drive during the startup process discussed in this article. Significant dynamic loads occur during the operation of manipulator cranes in the areas of transient processes. They lead to the swinging of the load on the articulated suspension. It leads to a decrease in the performance and reliability of the crane, as well as an increase in the energy consumption of the slewing mechanism drive. Optimization of the mode of movement of the mechanism of rotation of the crane-manipulator is carried out by minimizing the integral dynamic criterion, which is the root-mean-square value of the driving moment of the drive during the transition process. As a result of the optimization, a mode of starting the mechanism for turning the crane-manipulator was found, which reduces to a minimum power loading and fluctuations of the load on a hinged suspension in the radial direction. The obtained optimal start mode of the turning mechanism made it possible to increase the productivity and reliability of the crane-manipulator, as well as to reduce the energy costs of the driv

Retinoblastoma presentation, treatment and outcome in a large referral centre in Tehran: a 10-year retrospective analysis

Background/objectives: Early diagnosis, care and treatment of retinoblastoma is a challengeable issue for Iranian health system. This study was designed and conducted in a referral multidisciplinary centre in the capital city of Iran to evaluate management, care, prognosis and survival rates of paediatric patients with retinoblastoma. Methods: In this retrospective study, a total number of 309 patients younger than 15 years, diagnosed with retinoblastoma, who referred for diagnosis and treatment to MAHAK�s Pediatric Cancer Treatment and Research Center (MPCTRC) from 2007 to 2017 were evaluated. All data were analyzed via SPSS version 22 software in regard of parametric and non-parametric data. Survival rates were analyzed using the Kaplan�Meyer method. Results: The mean age of patients was 20 months and the majority of patients (77) had leukocoria as a common clinical symptom at the time of diagnosis. Primary treatment methods were systemic chemotherapy (94), laser (35) and primary enucleation (28). Relapses occurred in nearly 42 of cases, and the median time from diagnosis to the first relapse was 9 months. At the time analyzing the data, 11 of patients died. Patients� 5-year OS and RFS rates were 79.6 and 41.5, respectively. Conclusion: Comparing results with other conducted studies identifies that the recurrence rate was high in our considered patients. Also, OS and RFS rates in our study were not as considerable as other reports. Screening methods, updating protocols and follow-up of patients may lead to improvements in survival rates of patients with retinoblastoma. © 2020, The Author(s), under exclusive licence to The Royal College of Ophthalmologists